On Wed, 2019-05-15 at 15:34 -0400, Olga Kornievskaia wrote: > Sounds like we can't do: > const struct rpc_timeout *to = req->rq_task->tk_client- > >cl_timeout; > > Perhaps: > const struct rpc_timeout *to; > and check that if (!req->rq_task || !req->rq_task->tk_client) return > 0; > > Just a guess. Thoughts? All callers of call_decode() must have req->rq_task set, because there request must have sent an RPC call (so a slot must be allocated) and so we must have a task as the argument. I'm not sure about task->tk_client. I feel that should always be set here (again, since this is a reply) but it is possible there might be some code path where we're not setting that. I'd like to understand how, though: it certainly isn't the usual backchannel request. > > [37247.291617] BUG: unable to handle kernel NULL pointer dereference > at 0000000000000098 > [37247.296200] #PF error: [normal kernel read fault] > [37247.298110] PGD 0 P4D 0 > [37247.299264] Oops: 0000 [#1] SMP PTI > [37247.300729] CPU: 1 PID: 23870 Comm: kworker/u256:1 Not tainted > 5.1.0+ #172 > [37247.303547] Hardware name: VMware, Inc. VMware Virtual > Platform/440BX Desktop Reference Platform, BIOS 6.00 04/13/2018 > [37247.311770] Workqueue: rpciod rpc_async_schedule [sunrpc] > [37247.313958] RIP: 0010:xprt_adjust_timeout+0x9/0x110 [sunrpc] > [37247.316220] Code: c7 c7 20 0d 50 c0 31 c0 e8 68 00 e2 fc 41 c7 45 > 04 f4 ff ff ff eb c9 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 41 > 54 55 53 <48> 8b 87 98 00 00 00 48 89 fb 4c 8b 27 48 8b 80 a8 00 00 > 00 > 48 8b > [37247.323625] RSP: 0018:ffffb0ab84f5fd68 EFLAGS: 00010207 > [37247.325676] RAX: 00000000fffffff5 RBX: ffff9e0ff1042800 RCX: > 0000000000000003 > [37247.328433] RDX: ffff9e0ff11baac0 RSI: 00000000fffffe01 RDI: > 0000000000000000 > [37247.331206] RBP: ffff9e0fe20cb200 R08: ffff9e0ff11baac0 R09: > ffff9e0ff11baac0 > [37247.334038] R10: ffff9e0ff11baab8 R11: 0000000000000003 R12: > ffff9e1039b55050 > [37247.337098] R13: ffff9e0ff1042830 R14: 0000000000000000 R15: > 0000000000000001 > [37247.339966] FS: 0000000000000000(0000) GS:ffff9e103bc40000(0000) > knlGS:0000000000000000 > [37247.343261] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > [37247.345669] CR2: 0000000000000098 CR3: 000000007603a002 CR4: > 00000000001606e0 > [37247.348564] Call Trace: > [37247.351034] rpc_check_timeout+0x1d/0x140 [sunrpc] > [37247.353005] call_decode+0x13e/0x1f0 [sunrpc] > [37247.354893] ? rpc_check_timeout+0x140/0x140 [sunrpc] > [37247.357143] __rpc_execute+0x7e/0x3d0 [sunrpc] > [37247.359104] rpc_async_schedule+0x29/0x40 [sunrpc] > [37247.362565] process_one_work+0x16b/0x370 > [37247.365598] worker_thread+0x49/0x3f0 > [37247.367164] kthread+0xf5/0x130 > [37247.368453] ? max_active_store+0x80/0x80 > [37247.370087] ? kthread_bind+0x10/0x10 > [37247.372505] ret_from_fork+0x1f/0x30 > [37247.374695] Modules linked in: nfsv3 cts rpcsec_gss_krb5 nfsv4 > dns_resolver nfs rfcomm fuse ip6t_rpfilter ipt_REJECT nf_reject_ipv4 > ip6t_REJECT nf_reject_ipv6 xt_conntrack nf_conntrack nf_defrag_ipv6 > nf_defrag_ipv4 ebtable_nat ebtable_broute bridge stp llc > ip6table_mangle ip6table_security ip6table_raw iptable_mangle > iptable_security iptable_raw ebtable_filter ebtables ip6table_filter > ip6_tables iptable_filter bnep snd_seq_midi snd_seq_midi_event > crct10dif_pclmul crc32_pclmul ghash_clmulni_intel aesni_intel > crypto_simd cryptd glue_helper vmw_balloon snd_ens1371 snd_ac97_codec > uvcvideo ac97_bus snd_seq pcspkr btusb btrtl btbcm videobuf2_vmalloc > snd_pcm videobuf2_memops btintel videobuf2_v4l2 videodev bluetooth > snd_timer snd_rawmidi vmw_vmci snd_seq_device rfkill videobuf2_common > snd ecdh_generic i2c_piix4 soundcore nfsd nfs_acl lockd auth_rpcgss > grace sunrpc ip_tables xfs libcrc32c sr_mod cdrom sd_mod ata_generic > pata_acpi vmwgfx drm_kms_helper syscopyarea sysfillrect sysimgblt > fb_sys_fops > [37247.389774] ttm crc32c_intel drm serio_raw ahci ata_piix libahci > libata mptspi scsi_transport_spi e1000 mptscsih mptbase i2c_core > dm_mirror dm_region_hash dm_log dm_mod > [37247.437859] CR2: 0000000000000098 > [37247.462263] ---[ end trace 0d9a85f0df2cef9e ]--- -- Trond Myklebust Linux NFS client maintainer, Hammerspace trond.myklebust@xxxxxxxxxxxxxxx
